There are many different approaches to optical logic gates. For example, most optical logic gates are based on non-linear effects in optical fiber or in semiconductors. Most of these optical logic gates are based on interoferometric structures requiring a resonator and several structures to be coupled together to produce a complicated system.
Another technique includes molecular photonic gates that have shown promising results. However, these systems and methods have a drawback i.e., a majority work in a liquid state.
The above methods have switching times of around 10 to 100 ps wherein one (1) ps equals 10−12 seconds.
The systems and methods disclosed herein offer a different approach for producing optical logic gates then those mentioned above. Such systems and methods disclosed herein do not require a resonator structure. Accordingly, such systems and methods are much simpler, more condensed and work entirely in a solid state. Further, the systems operating time is theoretically very close to the above-mentioned methods around 100 ps more or less depending on the technology used.
Background for the present approach is disclosed in the following three U.S. patent application Publications and one U.S. patent. For example, a U.S. Patent Application Publication No. 2004/0156407 discloses quantum information processing using an electromagnetically induced transparency. This publication of Beausoleil et al. describes methods using photons and four-level matter systems in electromagnetically induced transparency (EIT) arrangements for one and two-qubit quantum gates, two-photon phase shifters and Bell State measurement devices. Further, as described electromagnetic pulses are propagated within a medium of two dipole moments of a three energy level system.
A second U.S. Patent Application Publication No. 2005/0185686 of Rupasov et al. describes nanophotonic devices based on quantum systems embedded in frequency band gap medium. The publication describes a system that is made of either atoms or artificial atoms or nano particles that have three energy levels. The publication describes nanophonic materials and devices for both classical and quantum optical signal processing, transmission, amplification and generation of light which are based on a set of quantum systems having discrete energy levels such as atoms, molecules, or quantum dots embedded in a frequency band gap medium such as artificial photonic crystals (photonic band gap materials) or natural frequency dispersive media, such as ionic molecular crystals or semiconductors exhibiting a frequency (photonic) band gap for propagating electromagnetic modes coupled to optical transitions in the quantum systems.
Further a U.S. Pat. No. 7,076,138 of Rupasov et al. describes nanophotonic devices based on quantum systems embedded in frequency band gap medium. The publication describes nanophotonic materials and devices for both classical and quantum optical signal processing, transmission, amplification and generation of light. The description is based on a set of quantum systems having discrete energy levels such as atoms, molecules or quantum dots embedded in a frequency band gap medium such as artificial photonic crystals (photonic band gap materials) or natural frequency dispersive media such as ionic crystals, molecular crystals, or semiconductors exhibiting a frequency (photonic) band gap for propagating electromagnetic modes coupled to optical transitions in the quantum systems.
Still further, a U.S. Patent Application Publication No. 2009/0297094 of Hochberg et al. describes an All-Optical Modulation And Switching With Patterned Optically Absorbing Polymers, in which AND, OR, XOR and XNOR work as logic gates. The publication describes processing devices that include patterned optically active polymers and are constructed according to principles of the invention to include at least one optical input port and at least one optical output port configured to accept optical input signals and provide optical output signals. The devices include optically active material such as organic polymers that interact with illumination at a first wavelength to change at least one optical property in a non-linear manner. The optically active polymer can be placed adjacent one or more waveguides that allow the input illumination to propagate. As the optical property of the optically active material is changed by the incident illumination, the propagating illumination undergoes a modulation or change in phase thereby providing an optical output signal having a desired relation to the optical input signal such as the result of a logical or a computational operation.
Notwithstanding the above, it is presently believed that there is a need and a potential commercial market for a new solid state nano-based optical logic gate and more particularly to an optical logic gate that includes an active band gap medium and a plurality of nano particles, homogeneous atoms or artificial atoms (quantum dots).